Question

Writing an assignment such as CONST = some_var will raise SyntaxError as Constant in ruby could not be reassigned.

But in some cases, I want to hold the current variable’s value in a constant and lock it there.

For example, when I initialize an instance from a class, I want to lock the passed in value within the instance. How should I do it the right way in ruby? (following is a illegal code in ruby trying to realize it, you get the idea)

class SomeClass
  def initialize(status)
    STATUS = status # it is illegal now
  end
end

Answer 1

The Ruby constants are expected to preserve the same value, it’s a recommendation, not a must:

A Ruby constant is like a variable, except that its value is supposed to remain constant for the duration of the program. The Ruby interpreter does not actually enforce the constancy of constants, but it does issue a warning if a program changes the value of a constant.